<template>
    <div class="content">
        <canvas class="snow" id="snow" width="1349" height="400"></canvas>
        <div class="main-text">
            <h1>404 天呐！出错了 ~<br><br>您好像去了一个不存在的地方！ (灬ꈍ ꈍ灬)</h1>
            <div class="main-text-a">
                <router-link to="/"> 返回首页</router-link>
            </div>
        </div>
        <div class="ground">
            <div class="mound">
                <div class="mound_text">404</div>
                <div class="mound_spade"></div>
            </div>
        </div>
    </div>
</template>

<script setup>
import { onMounted } from 'vue';
onMounted(() => {
    function ready(fn) {
        if (document.readyState != 'loading') {
            fn();
        } else {
            document.addEventListener('DOMContentLoaded', fn);
        }
    }

    function makeSnow(el) {
        var ctx = el.getContext('2d');
        var width = 0;
        var height = 0;
        var particles = [];

        var Particle = function () {
            this.x = this.y = this.dx = this.dy = 0;
            this.reset();
        }

        Particle.prototype.reset = function () {
            this.y = Math.random() * height;
            this.x = Math.random() * width;
            this.dx = (Math.random() * 1) - 0.5;
            this.dy = (Math.random() * 0.5) + 0.5;
        }

        function createParticles(count) {
            if (count != particles.length) {
                particles = [];
                for (var i = 0; i < count; i++) {
                    particles.push(new Particle());
                }
            }
        }

        function onResize() {
            width = window.innerWidth;
            height = window.innerHeight;
            el.width = width;
            el.height = height;

            createParticles((width * height) / 10000);
        }

        function updateParticles() {
            ctx.clearRect(0, 0, width, height);
            ctx.fillStyle = '#f6f9fa';

            particles.forEach(function (particle) {
                particle.y += particle.dy;
                particle.x += particle.dx;

                if (particle.y > height) {
                    particle.y = 0;
                }

                if (particle.x > width) {
                    particle.reset();
                    particle.y = 0;
                }

                ctx.beginPath();
                ctx.arc(particle.x, particle.y, 5, 0, Math.PI * 2, false);
                ctx.fill();
            });

            window.requestAnimationFrame(updateParticles);
        }

        onResize();
        updateParticles();
    }

    ready(function () {
        var canvas = document.getElementById('snow');
        makeSnow(canvas);
    });
})

</script>

<style scoped>
.content {
    height: 100%;
    width: 100%;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1;
    background-color: #d2e1ec;
    background-image: -webkit-linear-gradient(top, #bbcfe1 0%, #e8f2f6 80%);
    background-image: linear-gradient(to bottom, #bbcfe1 0%, #e8f2f6 80%);
    overflow: hidden;
}

.snow {
    position: absolute;
    top: 0;
    left: 0;
    pointer-events: none;
    z-index: 20;
}

.main-text {
    padding: 20vh 20px 0 20px;
    text-align: center;
    line-height: 2em;
    font-size: 5vh;
}

.main-text h1 {
    font-size: 45px;
    line-height: 48px;
    margin: 0;
    padding: 0;
}

.main-text-a {
    margin-left: auto;
    margin-right: auto;
    text-align: center;
}

.main-text-a a {
    font-size: 16px;
    text-decoration: none;
    color: #000;
}

.main-text-a a:hover {
    color: #000;
}

.home-link {
    font-size: 0.6em;
    font-weight: 400;
    color: inherit;
    text-decoration: none;
    opacity: 0.6;
    border-bottom: 1px dashed rgba(93, 115, 153, 0.5);
}

.home-link:hover {
    opacity: 1;
}

.ground {
    height: 160px;
    width: 100%;
    position: absolute;
    bottom: 0;
    left: 0;
    background: #f6f9fa;
    box-shadow: 0 0 10px 10px #f6f9fa;
}

.ground:before,
.ground:after {
    content: '';
    display: block;
    width: 250px;
    height: 250px;
    position: absolute;
    top: -62.5px;
    z-index: -1;
    background: transparent;
    -webkit-transform: scaleX(0.2) rotate(45deg);
    transform: scaleX(0.2) rotate(45deg);
}

.ground:after {
    left: 50%;
    margin-left: -166.66667px;
    box-shadow: -340px 260px 15px #8193b2, -620px 580px 15px #8193b2, -900px 900px 15px #b0bccf, -1155px 1245px 15px #b4bed1, -1515px 1485px 15px #8193b2, -1755px 1845px 15px #8a9bb8, -2050px 2150px 15px #91a1bc, -2425px 2375px 15px #bac4d5, -2695px 2705px 15px #a1aec6, -3020px 2980px 15px #8193b2, -3315px 3285px 15px #94a3be, -3555px 3645px 15px #9aa9c2, -3910px 3890px 15px #b0bccf, -4180px 4220px 15px #bac4d5, -4535px 4465px 15px #a7b4c9, -4840px 4760px 15px #94a3be;
}

.ground:before {
    right: 50%;
    margin-right: -166.66667px;
    box-shadow: 325px -275px 15px #b4bed1, 620px -580px 15px #adb9cd, 925px -875px 15px #a1aec6, 1220px -1180px 15px #b7c1d3, 1545px -1455px 15px #7e90b0, 1795px -1805px 15px #b0bccf, 2080px -2120px 15px #b7c1d3, 2395px -2405px 15px #8e9eba, 2730px -2670px 15px #b7c1d3, 2995px -3005px 15px #9dabc4, 3285px -3315px 15px #a1aec6, 3620px -3580px 15px #8193b2, 3880px -3920px 15px #aab6cb, 4225px -4175px 15px #9dabc4, 4510px -4490px 15px #8e9eba, 4785px -4815px 15px #a7b4c9;
}

.mound {
    margin-top: -80px;
    font-weight: 800;
    font-size: 180px;
    text-align: center;
    color: #dd4040;
    pointer-events: none;
}

.mound:before {
    content: '';
    display: block;
    width: 600px;
    height: 200px;
    position: absolute;
    left: 50%;
    margin-left: -300px;
    top: 50px;
    z-index: 1;
    border-radius: 100%;
    background-color: #e8f2f6;
    background-image: -webkit-linear-gradient(top, #dee8f1, #f6f9fa 60px);
    background-image: linear-gradient(to bottom, #dee8f1, #f6f9fa 60px);
}

.mound:after {
    content: '';
    display: block;
    width: 28px;
    height: 6px;
    position: absolute;
    left: 50%;
    margin-left: -150px;
    top: 68px;
    z-index: 2;
    background: #dd4040;
    border-radius: 100%;
    -webkit-transform: rotate(-15deg);
    transform: rotate(-15deg);
    box-shadow: -56px 12px 0 1px #dd4040, -126px 6px 0 2px #dd4040, -196px 24px 0 3px #dd4040;
}

.mound_text {
    -webkit-transform: rotate(6deg);
    transform: rotate(6deg);
}

.mound_spade {
    display: block;
    width: 35px;
    height: 30px;
    position: absolute;
    right: 50%;
    top: 42%;
    margin-right: -250px;
    z-index: 0;
    -webkit-transform: rotate(35deg);
    transform: rotate(35deg);
    background: #dd4040;
}

.mound_spade:before,
.mound_spade:after {
    content: '';
    display: block;
    position: absolute;
}

.mound_spade:before {
    width: 40%;
    height: 30px;
    bottom: 98%;
    left: 50%;
    margin-left: -20%;
    background: #dd4040;
}

.mound_spade:after {
    width: 100%;
    height: 30px;
    top: -55px;
    left: 0%;
    box-sizing: border-box;
    border: 10px solid #dd4040;
    border-radius: 4px 4px 20px 20px;
}
</style>